JPH07107023B2 - Lactic acid derivative and liquid crystal composition containing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lactic acid derivative having an easily changeable molecular structure and having optical activity, and a liquid crystal composition containing the same, and more specifically to an optically active lactic acid derivative. The present invention relates to a liquid crystal compound, a liquid crystal composition containing the same, and a liquid crystal device using the liquid crystal composition.

BACKGROUND ART Conventional liquid crystal elements include, for example, M.Sc
hadt) and W. Helfrich, ”
Applied, Physics, Letters "Volume 18, No. 4 (" Appl
ied Physics Letters ", Vol.18, No.4) (1971.2.15),
"Voltage-Dependent Optical Activity of a Tw."
It is known to use a TN (Twisted Nematic) liquid crystal described in "isted Nematic Liquid Crystal". However, this TN liquid crystal is used for time-division driving using a matrix electrode structure with a high pixel density. However, the number of pixels is limited because of the problem of crosstalk, and the use as a display is limited because of slow electric field response and poor viewing angle characteristics.

Furthermore, a display element of a type in which a switching element using a thin film transistor is connected to each pixel and switching is performed for each pixel is known, but a process of forming a thin film transistor on a substrate is extremely complicated, and a large area display element is used. There are problems that are difficult to create.

The use of bistability-type liquid crystal elements is one of the ways to improve the drawbacks of the conventional type liquid crystal elements.
ark) and Lagerwall (JP-A-56-107216, U.S. Pat. No. 4,367,924, etc.). As a liquid crystal having bistability, generally,
Chiral smectic C phase (SmC ^* ) or H phase (Sm
A ferroelectric liquid crystal having H ^* ) is used.

Since this ferroelectric liquid crystal has spontaneous polarization, it has a very fast response speed, and can express a bistable state with a memory property, and also has excellent viewing angle characteristics. Suitable as

Since the liquid crystalline compound used for the ferroelectric liquid crystal has an asymmetric carbon, it can be used for the following optical elements in addition to being used as the ferroelectric liquid crystal using the chiral smectic phase. Can be used.

1) Utilizing the cholesteric / nematic phase transition effect in the liquid crystal state (JJWysoki, A. Adams and WH
aas; Phys.Rev.Lett., 20,1024 (1968)), 2) Utilizing the white Taylor type guest-host effect in the liquid crystal state (DLWhite and GNTaylor;
J.Appl.Phys., 45 , 4718 (1974)), 3) By fixing the one that has a cholesteric phase in the liquid crystal state in the matrix, and utilizing its selective scattering characteristics, it can be used as a notch filter or bandpass filter. Things to do (FJKahn, Appl.Phys.Lett., 18,231
(1971)), which is used as a circular polarization beam splitter utilizing circular polarization characteristics (SDJacobs, SPIE, 37,98 (1
981)); etc.

A detailed description of each method is omitted, but all are important as a display element or a modulation element.

Conventionally, as an optically active intermediate for synthesizing a functional material required for an optical element characterized by having optical activity, 2-methylbutanol, secondary octyl alcohol,
Secondary butyl alcohol, p- (2-methylbutyl) chloride
Benzoic acid, secondary phenethyl alcohol, amino acid derivatives, camphor derivatives, cholesterol derivatives and the like are known.

However, these have the following drawbacks. The structure of the optically active chain hydrocarbon derivative is difficult to change, and, except for some, it is very expensive. Amino acid derivatives are relatively inexpensive and their structures can be easily modified, but the hydrogen groups of amines are chemically strongly active, and hydrogen bonding and chemical reactions are likely to occur, which tends to limit the properties of functional materials. . The camphor derivative and the cholesterol derivative are difficult to change their structures, and moreover, they tend to adversely affect the properties of the functional material due to steric hindrance.

The above-mentioned drawbacks have been a major limitation in developing various materials.

OBJECTS OF THE INVENTION In view of the above-mentioned circumstances, a main object of the present invention is to provide a compound which causes a large spontaneous polarization when used as a ferroelectric liquid crystal due to the presence of an enzyme atom adjacent to an asymmetric carbon atom. Especially.

Further, according to the present invention, it is easy to change the length of the alkyl group, which results in H. Arnold, Z. Phys. Chem ,. 226, 146 (1
964), it is an object of the present invention to provide a liquid crystal compound capable of controlling the type and temperature range of a liquid crystal phase that develops in a liquid crystal state, and a liquid crystal composition containing at least one compound component thereof. To do.

SUMMARY OF THE INVENTION That is, the present invention provides a compound represented by the general formula (I) (In the above general formula, R is a linear alkyl group having 1 to 18 carbon atoms, and X is (Wherein R ¹ is an alkyl group or an alkoxy group having 4 to 18 carbon atoms and m is 1 or 2), and a liquid crystal composition containing at least one of them as a blending component. And a liquid crystal device using the liquid crystal composition.

DETAILED DESCRIPTION OF THE INVENTION It is formally represented by the above general formula (I), wherein X is OH.
R, a halogen, a benzyloxy group, a phenoxy group, a toluenesulfonyloxy group, an acetyloxy group, a trifluoroacetyloxy group,
A liquid crystalline compound represented by the formula (I) of the present invention can be obtained by using as an precursor an optically active substance in which is a linear alkyl group having 1 to 18 carbon atoms. In the above optically active substance, R
Is 19 or more, the viscosity and molar volume of the final functional material are increased, which is not preferable. Moreover, the preferable number of carbon atoms of R is 4 to 16. Specific examples of R include linear alkyl group, branched alkyl group, cycloalkyl group, linear alkenyl group, branched alkenyl group, cycloalkenyl group, linear alkadienyl group, branched alkadienyl group, cyclo Examples include an alkadienyl group, a linear alkatrienyl group, a branched alkatrienyl group, a linear alkynyl group, a branched alkynyl group, and an aralkyl group. An alkyl group is particularly preferable for providing a liquid crystal compound described later. C ^* represents an asymmetric carbon atom. X is OH
Group, halogen, benzyloxy group, phenoxy group, toluenesulfonic acid group, acetyloxy group, trifluoroacetyloxy group, a substituent selected from other groups that reacts with the reaction reagent under appropriate reaction conditions Can be replaced with In this case, different liquid crystal compounds can be obtained by variously changing the reaction reagents.

In the liquid crystal compound of the invention thus obtained, X is (Wherein R ¹ is an alkyl group or an alkoxy group having 4 to 18 carbon atoms, and m is 1 or 2). In this case, the particularly preferable number of carbon atoms of R ¹ is 6 to 16.

Next, among the optically active lactic acid derivatives used as a precursor of the liquid crystalline compound of the present invention and formally represented by the general formula (I), compounds in which X is a removable chemically active substituent are An example of the synthesis method is shown below.

RI in the above reaction formula can be selected over a wide range of carbon numbers, and specifically, iodobutane, iodopentane, iodohexane, iodoheptane, iodooctane, iodononane, iododecane, iodoundecane, iododecane, iodotridecane. Linear saturated hydrocarbon iodides such as decane, iodotetradecane, iodopentadecane, iodohexadecane, iodoheptadecane, iodooctadecane, iodononadecane, iodoeicosane; 2-iodobutane, 1-iodo-2-methylpropane, 1-iodo Branched saturated hydrocarbon iodide such as -3-methylbutane; cyclic unsaturated hydrocarbon iodide such as iodobenzyl, iodophenacyl, 3-iodo-1-cyclohexene; iodocyclopentane, iodocyclohexane, 1-iodo- There are cyclic saturated hydrocarbon iodides such as 3-methylcyclohexane, iodocycloheptane, and iodocyclooctane.

An optically active lactic acid derivative can be obtained by freely selecting from the above iodides.

Table 1 shows the optical rotations of the thus obtained optically active lactic acid derivative which is a precursor of the liquid crystalline compound of the present invention.

From various lactic acid derivatives obtained by such a method,
The liquid crystal compound shown below is obtained by the synthetic route shown below.

(In the above, R, R ¹ , m and n are as defined above.) Table 2 shows examples of the liquid crystalline lactic acid derivative thus obtained.

The liquid crystal composition of the present invention contains at least one liquid crystalline lactic acid derivative represented by the above general formula (I) as a blending component.

Among the above-mentioned compositions, those containing a ferroelectric liquid crystal as represented by the following formulas (1) to (13) as a blending component can increase spontaneous polarization and further reduce the viscosity. This is preferable because it can improve the response speed. In such a case, the liquid crystalline lactic acid derivative of the present invention represented by the general formula (I) is preferably used in a ratio of 0.1 to 99% by weight, particularly preferably 1 to 90% by weight.

Further, by compounding with a smectic liquid crystal which is not chiral itself as shown in the following formulas 1) to 5), a composition usable as a ferroelectric liquid crystal can be obtained.

In such a case, the liquid crystalline lactic acid derivative of the present invention represented by the general formula (I) can be used in a ratio of 0.1 to 99% by weight.

Here, the symbols indicate the following phases, respectively.

Cryst .: Crystal phase, SmA: Smectic A phase, SmB: Smectic B phase, SmC: Smectic C
Phase, N: nematic phase, Iso .: isotropic phase.

The nematic liquid crystal containing the lactic acid derivative of the present invention as at least one compounding component is preferable because it can prevent the generation of reverse domains when it is used in a twisted nematic (TN) type cell.

When an element is constructed using these liquid crystal materials, in order to keep the liquid phase material in a temperature state where it is in the SmC ^* phase or SmH ^* phase, for example, the element may be a copper block with a heater embedded as necessary. Can be supported by.

FIG. 1 is a schematic drawing of an example of a cell for explaining the operation of the ferroelectric liquid crystal. 11a and 11b are respectively
A substrate (glass plate) covered with a transparent electrode composed of a thin film such as In ₂ O ₃ , SnO ₂ or ITO (Indium-Tin Oxide), in which the liquid crystal molecular layer 12 was oriented so that it was perpendicular to the glass surface. Liquid crystal of SmC ^* phase or SmH ^* phase is enclosed.
A thick line 13 represents a liquid crystal molecule, and this liquid crystal molecule 13 has a dipole moment (P _⊥ ) 14 in a direction orthogonal to the molecule. When a voltage above a certain threshold is applied between the electrodes on the substrates 21 and 11b, the helical structure of the liquid crystal molecules 13 is unraveled, and the dipole moment (P _⊥ ) 14 is oriented in the electric field direction. Can be changed. The liquid crystal molecule 13 has an elongated shape and exhibits refractive index anisotropy in the major axis direction and the minor axis direction thereof. Therefore, for example, if crossed Nicols polarizers are placed above and below the glass surface, the voltage application polarity is It can be easily understood that the liquid crystal optical modulation element changes its optical characteristics depending on the situation.

The liquid crystal cell preferably used in the optical modulator of the present invention can be made sufficiently thin (for example, 10 μm or less). As the liquid crystal layer becomes thinner, the helical structure of the liquid crystal molecules unwinds as shown in FIG. ) Takes either state. As shown in FIG. 2, electric fields Ea or Eb having different polarities, which are equal to or more than a certain threshold value, are applied to such a cell by the voltage applying means 21a.
And 21b, the dipole moment becomes the electric field Ea
Or 24a upward or 2 downward corresponding to the electric field vector of Eb
4b, and the liquid crystal molecules are aligned in either one of the first stable state 23a and the second stable state 23b accordingly.

As described above, there are two advantages of using such ferroelectricity as an optical modulation element.

The first is that the response speed is extremely fast, and the second is that the alignment of the liquid crystal molecules has bistability. The second point will be further explained with reference to FIG. 2, for example. When an electric field Ea is applied, the liquid crystal molecules are aligned in the first stable state 23a, but this state is stable even when the electric field is cut off. When an electric field Eb in the opposite direction is applied, the liquid crystal molecules are in the second stable state 23b.
The molecules are oriented to change their orientation, but they remain in this state even when the electric field is turned off. Further, unless the applied electric field Ea or Eb exceeds a certain threshold value, the previous orientation state is maintained. In order to effectively realize such a high response speed and bistability, it is preferable that the cell is as thin as possible, and generally 0.5 μ to 20 μ, particularly 1 μ to 5 μ is suitable.

Next, a specific example of the driving method of the ferroelectric liquid crystal will be described with reference to FIGS.

FIG. 3 is a schematic diagram of a cell 31 having a matrix electrode structure in which a ferroelectric liquid crystal compound (not shown) is sandwiched. Reference numeral 32 is a scan electrode group, and 33 is a signal electrode group.
First, the case where the scan electrode S ₁ is selected will be described. 4 (a) and 4 (b) show scanning signals, which are electric signals applied to the selected scanning electrode S ₁ and other scanning electrodes (non-selected scanning electrodes) S ₂ , S, respectively. ₃ , S ₄ ...
Shows an electric signal applied to. 4 (c) and 4 (d) show information signals which are electric signals applied to the selected signal electrodes I ₁ , I ₃ and I ₅ and the unselected signal electrodes I ₂ and I ₄ , respectively. Shows.

4 and 5, the horizontal axis represents time and the vertical axis represents voltage. For example, when displaying a moving image, the scan electrode groups 32 are sequentially and periodically selected.
Now, a threshold voltage for giving a first stable state of a liquid crystal cell having bistability with respect to a predetermined voltage application time t ₁ or t ₂ is −Vth _1, and a threshold value for giving a stable state of 2 is set. When the voltage is + Vth ₂ , the electrode signal applied to the selected scan electrode 32 (S ₁ ) is 2V at the phase (time) t _{1 and the} phase (time) t at the phase (time) t ₁ as shown in FIG. 4 (a). _{At 2} , the alternating voltage is −2V. When an electric signal having a plurality of phase intervals with different voltages is applied to the selected scan electrodes, the liquid crystal is switched between the first and second stable states corresponding to the optical "dark" or "bright" state. An important effect is that the state change of can be promptly caused.

On the other hand, the other scan electrodes S _{2 to} S ₅ ... Are in the ground state as shown in FIG.
Is. The electric signal applied to the selected signal electrodes I ₁ , I ₃ , I ₅ is V as shown in FIG. 4 (C), and the electric signal applied to the unselected signal electrodes I ₂ , I _4. The signal is -V as shown in Fig. 4 (d). In the above, each voltage value is set to a desired value that satisfies the following relationship.

V <Vth ₂ <3V −3V <−Vth ₁ <−V Among the respective pixels when such an electric signal is given, for example, the voltage waveforms applied to the pixels A and B in FIG. 5 is shown in FIGS. That is, as is apparent from FIGS. 5A and 5B, in the pixel A on the selected scan line, the voltage 3V exceeding the threshold value Vth ₂ is applied at the phase t ₂ . Further, in the pixel B existing on the same scanning line, the voltage −3V exceeding the threshold −Vth ₁ is applied at the phase t ₁ . Therefore, on the selected scan electrode line, depending on whether or not the signal electrode is selected, the liquid crystal molecules are aligned in the first stable state when selected, and the liquid crystal molecules are aligned in the first stable state when not selected. Align the orientation to the stable state of 2.

On the other hand, as shown in FIGS. 5 (c) and 5 (d), the voltage applied to all pixels is V
Or, it is -V, and neither exceeds the threshold voltage. Therefore, the liquid crystal molecules in each pixel other than on the selected scanning line maintain the orientation corresponding to the signal state at the time of the previous scanning without changing the orientation state. That is, when the scan electrode is selected, the signal for one line is written, and the signal state can be held until the end of one frame and the next selection. Therefore, even if the number of scanning electrodes is increased, there is no substantial duty ratio, and the contrast is not deteriorated at all.

Next, let us consider the problems that may actually occur when the display device is driven. In Figure 3,
Of the pixels formed at the intersections of the scan electrodes S _{1 to} S ₅ ... And the signal electrodes I _{1 to} I ₅ ..., the shaded pixels are in the “bright” state, and the pixels shown in white are the “dark”. It corresponds to the state.
Now, paying attention to the display on the signal electrode I _{1 in} FIG. 3, the pixel (A) corresponding to the scan electrode S ₁ is in the “bright” state, and the other pixels (B) are all in the “dark” state. Is. As an example of the driving method in this case, FIG. 6 shows the scanning signal, the information signal applied to the signal electrode I ₁ and the voltage applied to the pixel A in time series.

For example, when driven as shown in FIG. 6, the scanning signal S ₁
Is scanned, at time t ₂ , pixel A has a threshold Vth ₂
Since a voltage of 3 V exceeding 10 V is applied, the pixel A transitions (switches) to a unidirectional stable state, that is, a "bright" state regardless of the previous history. After that, as shown in FIG. 6, the voltage of −V is continuously applied while scanning S _{2 to} S ₅ ...
Since this does not exceed the threshold value −Vth ₁ , the pixel A should be able to maintain the “bright” state, but in reality, one signal electrode corresponds to one signal (in this case, “dark”). ) Is displayed continuously, the number of scanning lines is extremely large, and the inversion phenomenon occurs when high-speed driving is required. However, the above-mentioned specific liquid crystal compound or a liquid crystal composition containing it. By using, such inversion phenomenon is completely prevented.

Further, in the present invention, in order to prevent the above-mentioned inversion phenomenon, it is preferable to provide an insulating film formed of an insulating material on at least one of the counter electrodes constituting the liquid crystal cell.

The insulating material used at this time is not particularly limited, but silicon nitride, silicon nitride containing hydrogen, silicon carbide, silicon carbide containing hydrogen, silicon oxide, boron nitride, hydrogen. Containing boron nitride, cerium oxide, aluminum oxide, zirconium oxide, inorganic insulating materials such as titanium oxide and magnesium fluoride, or polyvinyl alcohol, polyimide, polyamide imide, polyester imide, polyparaxylene, polyester, An organic insulating material such as polycarbonate, polyvinyl acetal, polyvinyl chloride, polyvinyl acetate, polyamide, polystyrene, cellulose resin, melamine resin, urea resin, acrylic resin or photoresist resin is used as the insulating film. The thickness of these insulating films is 5000 Å or less, preferably 100 Å ~ 1
000Å, especially 500Å ~ 3000Å are suitable.

Effects of the Invention At least 1 of the optically active liquid crystalline lactic acid derivative of the present invention is used.
The liquid crystal composition containing a kind as a blending component,
By using it as a chiral nematic liquid crystal or a chiral smectic liquid crystal, it is possible to improve response speed and prevent reverse domain from occurring by increasing spontaneous polarization and adjusting viscosity.

Hereinafter, the optically active substance as a precursor, and the liquid crystalline lactic acid derivative and liquid crystal composition of the present invention will be described in detail by reference examples and examples.

Reference Example 1 p-Hydroxybenzoic acid (2-ethoxy) propyl ester "SOCl _{2 (} 165 g) was added with P-acetyloxybenzoic acid (50 g) at 60 ° C.
Heated at 40 minutes. After cooling, the solvent is distilled off, 64.5 g was obtained.

2-ethoxy-propanol ^{_{(C 2 H 5 OC * H}} (CH 3) CH 2 OH)
10 g and 11.6 g of N, N-dimethylaniline were dissolved in 20 ml of ether and obtained as above under stirring. 22.3 g was added dropwise in 45 minutes. Then heat to reflux for 1 hour 30
Stir for minutes.

Water was added and the ether layer was separated and purified to obtain p-acetyloxybenzoic acid (2-ethoxy) propyl ester. After adding methanol to it, a mixed solution of methanol: 28% ammonia water = 1: 1 was added and stirred for hydrolysis.

It was extracted with 400 ml of ether, washed with water, dried (Na ₂ SO ₄ ) and the solvent was distilled off to obtain 11.5 g of a crude product. Column purification with 1 kg of silica gel (mobile phase: isopropyl ether: n-hexane = 1: 1) gave 6.4 g of p-hydroxybenzoic acid (2-ethoxy) propyl ester.

The following IR data was obtained for the product.

IR (cm ^-1 ): p-acetyloxybenzoic acid (2-ethoxy) propyl ester 2980, 2880, 1770, 1720, 1610, 1505, 1375, 1275, 1200, 1160, 1120, 1100.

p-Hydroxybenzoic acid (2-ethoxy) propyl ester 3310, 2990, 2900, 1720, 1700, 1620, 1600, 1520, 1450, 1390, 1280, 1170, 1100.

Reference Example 2 p-Hydroxybenzoic acid (2-propoxy) propyl ester By the same operation as in Reference Example 1, 14.6 g of p-hydroxybenzoic acid (2-propoxy) propyl ester was obtained from 10 g of (2-propoxy) propanol. It was

The following IR and NMR data were obtained on the product.

IR: 3370, 3000, 2900, 1720, 1700, 1625, 1610, 1525, 1460, 1395, 1280, 1250, 1180, 1120. ¹ H-NMR 0.9 to 1.8 ppm (8H), 2.3 ppm (1H), 3.4 to 4.3 ppm (5
H), 6.7 to 8.0 ppm (4H).

Reference Examples 3 to 5 By the same operation as in Reference Example 1, the lactic acid derivative of the present invention was obtained. The products, along with their specific rotations, are as set forth in Table 1 above.

Reference Example 6 p-Hydroxybiphenylcarboxylic acid (2-pentyloxy) propyl ester KOH9.42 g (1.68 × 10 ^-1 mol)
15 g (7.02 × 10 ^-2 mol) of p-hydroxybiphenylcarboxylic acid was added dropwise to 10 ml of the above solution at room temperature over 10 minutes. After the dropping, the precipitated crystals were filtered and recrystallized with water to obtain 5.9 g of p-acetyloxybiphenylcarboxylic acid. (Yield: 32.9%) To 20 g (1.68 × 10 ^-1 mol) of SOCl ₂ was added 5.7 g (2.23 × 10 ^-2 mol) of p-acetyloxybiphenylcarboxylic acid to give 3.5.
Heated to reflux for hours. After cooling, the solvent was distilled off to obtain 7.0 g of p-acetyloxybiphenylcarboxylic acid chloride.

2-pentyloxyheptanol 3.25 g (2.23 × 10 ^-2 mo
l), 2.69 g (2.23 × 10 ^-2 mol) of N, N-dimethylaniline was dissolved in 10 ml of ether, and a solution of 20 ml of toluene of p-acetyloxybiphenylcarboxylic acid chloride synthesized above was stirred at room temperature under stirring. It dripped over minutes. After the dropping, the mixture was heated under reflux for 7 hours.

After completion of the reaction, 50 ml of water was added to dissolve the crystals and the mixture was extracted 3 times with 30 ml of ether. The ether layer was washed 4 times with 50 ml of a 10% H ₂ SO ₄ aqueous solution and 3 times with water, dried over anhydrous sodium sulfate and then the solvent was distilled off to obtain 20.3 g of an oily substance. This was purified by silica gel column chromatography to obtain 8.6 g of p-acetyloxybiphenylcarboxylic acid (2-pentyloxy) propyl ester.

The p-acetyloxybiphenylcarboxylic acid (2-pentyloxy) propyl ester obtained above was added to methanol.
After diluting with 50 ml, methanol: NH ₄ OH (28%) = 1: 1
Was added with stirring to hydrolyze. Then, the mixture was extracted 3 times with anhydrous sodium sulfate, the ether layer was washed 3 times with 50 ml of water, dried over anhydrous sodium sulfate and the solvent was distilled off to obtain an oily substance. This was purified by silica gel column chromatography to obtain 2.6 g of p-hydroxybiphenylcarboxylic acid (2-pentyloxy) propyl ester.

The following IR data was obtained for the product.

IR: 3400, 2950, 2875, 1720, 1700, 1615, 1600, 1450, 1380, 1290, 1260, 1110.

Example 3 p′-decyloxybiphenylcarboxylic acid p ″ (2-ethoxypropyloxycarbonyl) phenyl ester decyloxybiphenylcarboxylic acid 4 g (113 × 10 ⁻² mol)
20 ml of SOCl ₂ was added to the mixture, and the mixture was heated under reflux for 3.5 hours. Excess SOCl
₂ was distilled off to obtain decyloxybiphenylcarboxylic acid chloride.

The obtained acid chloride was dissolved in 10 ml of toluene, and dissolved in 16 ml of pyridine. 2.35 g (1.13 × 10 ^-2 mol) of optically active p-hydroxybenzoic acid 2-ethoxypropyl ester.
The mixture was added dropwise to the mixture, left at room temperature for 55 minutes, and then stirred for 3 hours and 50 minutes.

The reaction mixture was extracted into cold water, washed with 6N HCl solution and water, dried and evaporated to remove 4.4 g of p'-decyloxybiphenylcarboxylic acid p "(2-ethoxypropyloxycarbonyl) phenyl ester. After further purification by silica gel column chromatography, recrystallization was performed 1.
8 g of purified product was obtained.

The following IR and NMR data were obtained on the product.

IR: 2940, 2870, 1740, 1610, 1515, 1480, 1395, 1295, 1135, 1090. ¹ H-NMR: 6.8 to 8.2 ppm (12H), 3.3 to 4.3 ppm (7H), 0.8 to 1.8 ppm
(25H).

Examples 1, 2, 4 to 9, 10, 11 Liquid crystal compounds were obtained in the same manner as in Example 3.

The products, as well as their phase transition temperatures, are as shown in Table 2 above.

Example 12 Liquid crystal device using the liquid crystalline compound produced in Example 3 An ITO film of about 1000Å was provided as an electrode on a glass of 10 × 20 mm which was highly accurately polished, and about 1000Å of SiO ₂ was vapor-deposited by the ion beam method. . The liquid crystalline compound produced in Example 9 was dropped on the glass substrate processed in the same manner, and the above glass substrates were laminated facing each other. When the substrates were held at 160 ° C and the substrates were held parallel to each other under a polarizing microscope while keeping the space between the upper and lower substrates, the horizontally aligned monodomains were obtained. The liquid crystal layer thickness at that time was 1.4 μm, and switching was performed in about 100 μsec when a pulse of ± 10 V was applied at 80 ° C.

Example 13 Characteristics of liquid crystal composition containing the liquid crystalline compound produced in Example 4 as a compounding component And a liquid crystal compound of Example 4 (79 wt%) showed SmC ^* at 20 to 90 ° C. in the cooling process.

Example 14 A polyimide film having a film thickness of 1000 Å was formed on each of opposing matrix electrodes formed of crossed strip ITO (5 of polyamic acid resin composed of a combination of pyromellitic anhydride and 4,4′-diaminodiphenyl ether). A N-methylpyrrolidone solution (wt%) was applied, and a ring closure reaction was performed at a temperature of 250 ° C.), and the surfaces of this polyimide film were rubbed so as to be parallel to each other to form a cell having a cell thickness of 1 μm. did.

Then, the following composition A was injected into the above-mentioned cell under an isotropic phase by a vacuum injection method and sealed. After that, a SmC ^* liquid crystal cell was prepared by slow cooling (1 ° C./hour).

Liquid crystal composition A: A crossed Nicol polarizer and an analyzer were arranged on both sides of the liquid crystal cell, and signals having the waveforms shown in FIGS. 4 and 5 were applied between the opposed matrix electrodes. At this time, the scanning signal is an alternating waveform of +8 volts and -8 volts shown in FIG. 4 (a),
The writing information was +4 volt and -4 volt, respectively. Also, one frame period is set to 30 msec.

As a result, even when the liquid crystal element was subjected to the memory drive type time division drive described above, a normal moving image display was obtained without any inversion of the written state.

Comparative Example 1 Liquid crystal composition A used in producing the liquid crystal element of Example 14
A liquid crystal element was prepared by preparing the following comparative liquid crystal B in which the liquid crystal compound represented by the above general formula (I) was omitted. These liquid crystal elements were driven by the same method as described above, but a normal moving image was not displayed due to the inversion phenomenon.

Comparative LCD B:

[Brief description of drawings]

1 and 2 are perspective views schematically showing a time-division driving liquid crystal element used in the present invention, FIG. 3 is a plan view of a matrix electrode structure used in the present invention, and FIGS.
(D) is an explanatory view showing an electric signal applied to the matrix electrode, FIGS. 5 (a) to (d) are explanatory views showing a waveform of a voltage applied between the matrix electrodes, and FIG. It is explanatory drawing of the time chart showing the electric signal applied to the liquid crystal element of this invention. 11a, 11b ... Substrate, 12 ... Liquid crystal molecule layer, 13 ... Liquid crystal molecule, 14 ... Dipole moment (P _⊥ ), 23a ... First stable state, 23b ... Second stable state, 24a ...... Upward dipole moment, 24b …… Downward dipole moment, 31 …… Cell, 32 …… (S ₁ , S ₂ , S ₃ , ・ ・ ・)… Scan electrode group, 33 …… (I ₁ , I ₂ , I ₃ , ...) ... Signal electrode group.

Claims (3)

[Claims] 1. A general formula (I) (In the above general formula, R represents a linear alkyl group having 1 to 18 carbon atoms. N is 1 or 2, C ^* represents an asymmetric carbon atom. X represents X. (Provided that R ¹ is an alkyl group or an alkoxy group having 4 to 18 carbon atoms and m is 1 or 2)). 2. General formula (I) (In the above general formula, R represents a linear alkyl group having 1 to 18 carbon atoms. N is 1 or 2, C ^* represents an asymmetric carbon atom. X represents X. (Wherein R ¹ is an alkyl group or an alkoxy group having 4 to 18 carbon atoms and m is 1 or 2)) and at least one liquid crystal lactic acid derivative is contained as a compounding component. Composition. 3. General formula (I) (In the above general formula, R represents a linear alkyl group having 1 to 18 carbon atoms. N is 1 or 2, C ^* represents an asymmetric carbon atom. X represents X. (Wherein R ₁ is an alkyl group or an alkoxy group having 4 to 18 carbon atoms and m is 1 or 2)) and a liquid crystal composition containing at least one liquid crystalline lactic acid derivative as a compounding component is used. A liquid crystal element characterized by the above.